本發明之光學玻璃以莫耳%計，含有SiO2
成分20.0～65.0%、Nb2
O5
成分1.0～25.0%及Na2
O成分1.0～35.0%，具有1.62以上且1.75以下之折射率(nd
)、30以上且42以下之阿貝數(νd
)、及0.594以下之部分分散比(θg，F)。 可於含有SiO2
成分及Nb2
O5
成分之玻璃中，獲得具有所需之範圍內之較高之折射率或較低之阿貝數(較高之分散)、及較低之部分分散比之玻璃。 因此，可獲得一種具有所需之較高之折射率(nd
)及較低之阿貝數(νd
)，且部分分散比(θg，F)較小，對降低光學系統之色像差有用之光學玻璃。 此外，可獲得一種因對玻璃進行再加熱時之失透減少故而適於再加熱加壓成形之光學玻璃。 又，亦可獲得一種因比重較小而有助於光學設備之輕量化，又，因玻璃轉移點較低而可降低再加熱加壓成形時之加熱溫度之光學玻璃。 以下，對本發明之光學玻璃之實施形態詳細地進行說明，但本發明並不受以下之實施形態任何限定，於本發明之目的之範圍內，可適當地加以變更進行實施。再者，存在對於說明發生重複之處適當地省略說明之情形，但並非限定發明之主旨者。 [玻璃成分] 以下，說明構成本發明之光學玻璃之各成分之組成範圍。本說明書中，於無特殊說明之情形時，各成分之含量均為以氧化物換算組成之相對於玻璃之總莫耳數之莫耳%所表示者。此處，所謂「氧化物換算組成」，係指如下組成：於假定用作本發明之玻璃構成成分之原料之氧化物、複合鹽、金屬氟化物等於熔融時全部分解變為氧化物之情形時，將該生成氧化物之總莫耳數設為100莫耳%來表示玻璃中所含有之各成分。 ＜關於必需成分、任意成分＞ SiO2
成分係促進玻璃穩定地形成，減少作為光學玻璃所欠佳之失透(結晶物之產生)之必需成分。 尤其是藉由將SiO2
成分之含量設為20.0%以上，可不大幅提高部分分散比而減少失透。又，藉此，可減少再加熱時之失透或著色。因此，SiO2
成分之含量較佳為設為20.0%以上，更佳為設為超過30.0%，進而較佳為設為超過35.0%，進而較佳為設為超過40.0%，進而較佳為設為超過43.0%，進而較佳為設為超過45.0%。 另一方面，藉由將SiO2
成分之含量設為65.0%以下，折射率不易變低，故可容易獲得所需之高折射率，並且可抑制部分分散比之上升。又，藉此，可抑制玻璃原料之熔解性之降低。因此，SiO2
成分之含量較佳為設為65.0%以下，更佳為設為未達60.0%，進而較佳為設為未達58.0%，進而較佳為設為未達55.0%。 SiO2
成分可使用SiO2
、K2
SiF6
、Na2
SiF6
等作為原料。 Nb2
O5
成分係藉由含有1.0%以上而可提高玻璃之折射率，並可降低阿貝數及部分分散比之必需成分。因此，Nb2
O5
成分之含量較佳為設為1.0%以上，更佳為設為超過3.0%，進而較佳為設超過5.0%，進而較佳為設超過7.0%。 另一方面，藉由將Nb2
O5
成分之含量設為25.0%以下，可降低玻璃之材料成本。又，可抑制玻璃製造時之熔解溫度之上升，並且減少由Nb2
O5
成分之過量之含有所引起之失透。因此，Nb2
O5
成分之含量較佳為設為25.0%以下，更佳為設為未達20.0%，進而較佳為設為未達15.0%，進而較佳為設為未達11.0%，進而較佳為設為未達10.0%。 Nb2
O5
成分可使用Nb2
O5
等作為原料。 Na2
O成分係藉由含有1.0%以上而可降低玻璃之部分分散比，提高再加熱加壓性，降低玻璃轉移點，並且提高玻璃原料之熔解性之必需成分。因此，Na2
O成分之含量較佳為設為1.0%以上，更佳為設為超過5.0%，進而較佳為設為超過8.0%，進而較佳為設為超過11.0%，進而較佳為設為超過13.0%，進而較佳為設為超過15.0%。 另一方面，藉由將Na2
O成分之含量設為35.0%以下，可抑制玻璃之折射率之降低，可使化學耐久性不易變差，且可減少由過量之含有所引起之失透。 因此，Na2
O成分之含量較佳為設為35.0%以下，更佳為設為未達30.0%，進而較佳為設為未達25.0%，進而較佳為設為未達23.0%。 Na2
O成分可使用Na2
CO3
、NaNO3
、NaF、Na2
SiF6
等作為原料。 SiO2
成分、Nb2
O5
成分及Li2
O成分之合計量(莫耳和)較佳為25.0%以上且70.0%以下。 尤其是藉由將該合計量設為25.0%以上，可提高玻璃之再加熱加壓性。因此，莫耳和(SiO2
＋Nb2
O5
＋Li2
O)較佳為設為25.0%以上，更佳為設為超過30.0%，進而較佳為設為超過40.0%，進而較佳為設為超過50.0%，進而較佳為設為超過54.0%，進而較佳為設為58.05%以上。 另一方面，藉由將該合計量設為70.0%以下，可減少玻璃之失透。因此，莫耳和(SiO2
＋Nb2
O5
＋Li2
O)較佳為將70.0%設為上限，更佳為將68.0%設為上限，進而較佳為將65.0%設為上限。 B2
O3
成分係於含有超過0%之情形時，可促進玻璃穩定地形成而減少失透，並且可提高玻璃原料之熔解性之任意成分。因此，B2
O3
成分之含量亦可較佳為設為超過0%，更佳為設為超過1.0%，進而較佳為設為超過2.0%，進而較佳為設為超過4.0%，進而較佳為設為超過6.0%，進而較佳為設為超過7.0%，進而較佳為設為超過10.0%，進而較佳為設為超過12.0%。 另一方面，藉由將B2
O3
成分之含量設為30.0%以下，可抑制折射率之降低或阿貝數之上升，並且可抑制部分分散比之上升。因此，B2
O3
成分之含量較佳為設為30.0%以下，更佳為設為未達25.0%，進而較佳為設為未達20.0%，進而較佳為設為未達18.0%。 B2
O3
成分可使用H3
BO3
、Na2
B4
O7
、Na2
B4
O7
・10H2
O、BPO4
等作為原料。 ZrO2
成分係於含有超過0%之情形時，可提高玻璃之折射率，降低阿貝數，降低部分分散比，並且可減少失透之任意成分。又，藉此，可減少再加熱時之失透或著色。因此，ZrO2
成分之含量亦可較佳為設為超過0%，更佳為設為超過0.5%，更佳為設為超過1.0%，進而較佳為設為超過3.0%，進而較佳為設為超過5.0%。 另一方面，藉由將ZrO2
成分之含量設為20.0%以下，可減少失透，並可容易獲得更均質之玻璃。因此，ZrO2
成分之含量較佳為設為20.0%以下，更佳為設為未達15.0%，進而較佳為設為未達12.0%，進而較佳為設為未達10.0%，進而較佳為設為未達9.0%。 ZrO2
成分可使用ZrO2
、ZrF4
等作為原料。 Li2
O成分係於含有超過0%之情形時，可降低玻璃之部分分散比，提高再加熱加壓性，降低玻璃轉移點，並且可提高玻璃原料之熔解性之任意成分。因此，Li2
O成分之含量亦可較佳為設為超過0%，更佳為設為超過0.3%，進而較佳為設為超過0.5%。 另一方面，藉由將Li2
O成分之含量設為20.0%以下，可抑制折射率之降低，使化學耐久性不易變差，且可減少由過量之含有所引起之失透。 因此，Li2
O成分之含量較佳為設為20.0%以下，更佳為設為未達15.0%，進而較佳為設為未達12.0%，進而較佳為設為未達10.0%。 Li2
O成分可使用Li2
CO3
、LiNO3
、LiF等作為原料。 TiO2
成分係於含有超過0%之情形時，可提高折射率，降低阿貝數，並且減少失透之任意成分。 另一方面，藉由將TiO2
成分之含量設為15.0%以下，可減少玻璃之著色，提高內部透過率。又，藉此，部分分散比變得不易上升，因此可容易獲得所需之較低之部分分散比。因此，TiO2
成分之含量較佳為設為15.0%以下，更佳為設為未達12.0%，進而較佳為設為未達10.0%，進而較佳為設為未達5.0%，進而較佳為設為未達3.0%。 TiO2
成分可使用TiO2
等作為原料。 K2
O成分係於含有超過0%之情形時，可降低折射率，提高玻璃原料之熔解性，並且降低玻璃轉移點之任意成分。 另一方面，藉由將K2
O成分之含量設為10.0%以下，可抑制部分分散比之上升，減少失透，並且可使化學耐久性不易變差。又，可抑制再加熱加壓成形性之降低。因此，K2
O成分之含量較佳為設為10.0%以下，更佳為設為未達5.0%，進而較佳為設為未達3.0%，進而較佳為設為未達1.5%，進而較佳為設為未達0.5%。 K2
O成分可使用K2
CO3
、KNO3
、KF、KHF2
、K2
SiF6
等作為原料。 MgO成分係於含有超過0%之情形時，可降低玻璃之熔解溫度之任意成分。 另一方面，藉由將MgO成分之含量設為10.0%以下，可抑制折射率之降低或阿貝數之上升，並且可減少失透。因此，MgO成分之含量較佳為設為10.0%以下，更佳為設為未達5.0%，進而較佳為設為未達3.0%，進而較佳為設為未達1.0%。 MgO成分可使用MgO、MgCO3
、MgF2
等作為原料。 CaO成分係於含有超過0%之情形時，可降低玻璃之材料成本，並減少失透，且可提高玻璃原料之熔解性之任意成分。 另一方面，藉由將CaO成分之含量設為15.0%以下，可抑制折射率之降低或阿貝數之上升，抑制部分分散比之上升，並且可減少失透。因此，CaO成分之含量較佳為設為15.0%以下，更佳為設為未達10.0%，進而較佳為設為未達5.0%，進而較佳為設為未達2.5%。 CaO成分可使用CaCO3
、CaF2
等作為原料。 SrO成分係於含有超過0%之情形時，可減少玻璃之失透，並且提高折射率之任意成分。 尤其是藉由將SrO成分之含量設為15.0%以下，可抑制阿貝數之上升，並且抑制化學耐久性之變差。因此，SrO成分之含量較佳為設為15.0%以下，更佳為設為未達10.0%，進而較佳為設為未達5.0%，進而較佳為設為未達3.0%，進而較佳為設為未達1.0%。 SrO成分可使用Sr(NO3
)2
、SrF2
等作為原料。 BaO成分係於含有超過0%之情形時，可減少玻璃之失透，並且提高折射率，提高玻璃原料之熔解性，且與其他鹼土族成分相比可降低玻璃之材料成本之任意成分。又，亦為可抑制再加熱加壓成形性之降低之成分。 另一方面，藉由將BaO成分之含量設為25.0%以下，可抑制阿貝數之上升，並且抑制化學耐久性之變差、或失透。因此，BaO成分之含量較佳為設為25.0%以下，更佳為設為未達15.0%，進而較佳為設為未達10.0%，進而較佳為設為未達5.0%。 BaO成分可使用BaCO3
、Ba(NO3
)2
等作為原料。 La2
O3
成分、Gd2
O3
成分、Y2
O3
成分及Yb2
O3
成分係藉由含有至少任一者超過0%而可提高折射率，且降低部分分散比之任意成分。 另一方面，藉由將La2
O3
成分之含量設為15.0%以下，可抑制阿貝數之上升，減小比重，並且可減少失透。因此，La2
O3
成分之含量較佳為設為15.0%以下，更佳為設為未達10.0%，進而較佳為設為未達5.0%，進而較佳為設為未達3.0%，進而較佳為設為未達1.0%。 又，藉由將Y2
O3
成分之含量設為20.0%以下，可抑制阿貝數之上升，減小比重，減少失透。因此，Y2
O3
成分之含量較佳為設為20.0%以下，更佳為設為未達10.0%，進而較佳為設為未達5.0%，進而較佳為設為未達3.0%。 又，藉由將Gd2
O3
成分及Yb2
O3
成分各者之含量設為10.0%以下，可抑制阿貝數之上升，減小比重，減少失透，且可降低材料成本。因此，Gd2
O3
成分及Yb2
O3
成分各者之含量較佳為設為10.0%以下，更佳為設為未達5.0%，進而較佳為設為未達3.0%，進而較佳為設為未達1.0%。 La2
O3
成分、Gd2
O3
成分、Y2
O3
成分及Yb2
O3
成分可使用La2
O3
、La(NO3
)3
・XH2
O(X為任意之整數)、Y2
O3
、YF3
、Gd2
O3
、GdF3
、Yb2
O3
等作為原料。 P2
O5
成分係於含有超過0%之情形時，可減少玻璃之失透之任意成分。 另一方面，藉由將P2
O5
成分之含量設為10.0%以下，可減少由P2
O5
成分之過量之含有所引起之失透。因此，P2
O5
成分之含量較佳為設為10.0%以下，更佳為設為未達5.0%，進而較佳為設為未達3.0%，進而較佳為設為未達1.0%。 P2
O5
成分可使用Al(PO3
)3
、Ca(PO3
)2
、Ba(PO3
)2
、BPO4
、H3
PO4
等作為原料。 GeO2
成分係於含有超過0%之情形時，可提高折射率並且減少失透之任意成分。 另一方面，藉由將GeO2
成分之含量設為10.0%以下，因昂貴之GeO2
成分之使用量減少，故可降低玻璃之材料成本。因此，GeO2
成分之含量較佳為設為10.0%以下，更佳為設為未達5.0%，進而較佳為設為未達1.0%。 GeO2
成分可使用GeO2
等作為原料。 Al2
O3
成分及Ga2
O3
成分係於含有至少任一者超過0%之情形時，可提高化學耐久性，並且減少玻璃之失透之任意成分。 另一方面，藉由將Al2
O3
成分之含量設為15.0%以下，可減少由過量之含有所引起之失透。因此，Al2
O3
成分之含量較佳為設為15.0%以下，更佳為設為未達8.0%，進而較佳為設為未達5.0%，進而較佳為設為未達3.0%。 又，藉由將Ga2
O3
成分之含量設為10.0%以下，可減少由過量之含有所引起之失透。因此，Ga2
O3
成分之含量較佳為設為10.0%以下，更佳為設為未達5.0%，進而較佳為設為未達3.0%。 Al2
O3
成分及Ga2
O3
成分可使用Al2
O3
、Al(OH)3
、AlF3
、Ga2
O3
、Ga(OH)3
等作為原料。 Ta2
O5
成分係於含有超過0%之情形時，可提高折射率，降低部分分散比，且可減少玻璃之失透之任意成分。 另一方面，藉由將Ta2
O5
成分之含量設為10.0%以下，因作為稀有礦物資源之Ta2
O5
成分之使用量減少，且玻璃變得容易於更低溫下熔解，故可減少玻璃之生產成本。又，藉此，可減少由Ta2
O5
成分之過量含有所引起之玻璃之失透、或阿貝數之上升。因此，Ta2
O5
成分之含量較佳為設為10.0%以下，更佳為設為未達5.0%，進而較佳為設為未達3.0%，進而較佳為設為未達1.0%。尤其是就降低玻璃之材料成本之觀點而言，亦可將Ta2
O5
成分之含量設為未達0.1%。 Ta2
O5
成分可使用Ta2
O5
等作為原料。 WO3
成分係於含有超過0%之情形時，可提高折射率，降低阿貝數，減少玻璃之失透，且可提高玻璃原料之熔解性之任意成分。 另一方面，藉由將WO3
成分之含量設為10.0%以下，可使玻璃之部分分散比難以上升，且可減少玻璃之著色，提高內部透過率。因此，WO3
成分之含量較佳為設為10.0%以下，更佳為設為未達5.0%，進而較佳為設為未達3.0%，進而較佳為設為未達1.0%。 WO3
成分可使用WO3
等作為原料。 Bi2
O3
成分係於含有超過0%之情形時，可提高折射率，降低阿貝數，且可降低玻璃轉移點之任意成分。 另一方面，藉由將Bi2
O3
成分之含量設為10.0%以下，可使部分分散比不易上升，且可減少玻璃之著色，提高內部透過率。因此，Bi2
O3
成分之含量較佳為設為10.0%以下，更佳為設為未達5.0%，進而較佳為設為未達3.0%，進而較佳為設為未達1.0%。 Bi2
O3
成分可使用Bi2
O3
等作為原料。 ZnO成分係於含有超過0%之情形時，可減少玻璃之失透，降低部分分散比，且可降低玻璃轉移點之任意成分。 另一方面，藉由將ZnO成分之含量設為20.0%以下，可減少玻璃之再加熱時之失透或著色，並且可提高化學耐久性。因此，ZnO成分之含量較佳為設為20.0%以下，更佳為設為未達10.0%，進而較佳為設為未達5.0%，進而較佳為設為未達3.0%。 ZnO成分可使用ZnO、ZnF2
等作為原料。 TeO2
成分係於含有超過0%之情形時，可提高折射率，降低部分分散比，且可降低玻璃轉移點之任意成分。 另一方面，藉由將TeO2
成分之含量設為10.0%以下，可減少玻璃之著色，提高內部透過率。又，藉由減少昂貴之TeO2
成分之使用，可獲得材料成本更低之玻璃。因此，TeO2
成分之含量較佳為設為10.0%以下，更佳為設為未達5.0%，進而較佳為設為未達3.0%，進而較佳為設為未達1.0%。 TeO2
成分可使用TeO2
等作為原料。 SnO2
成分係於含有超過0%之情形時，可使熔解之玻璃澄清(消泡)之任意成分。 另一方面，藉由將SnO2
成分之含量設為5.0%以下，可使由熔融玻璃之還原所引起之玻璃之著色、或玻璃之失透不易發生。又，由於SnO2
成分與熔解設備(尤其是Pt等貴金屬)之合金化降低，故而可謀求熔解設備之長壽化。因此，SnO2
成分之含量較佳為設為5.0%以下，更佳為設為未達3.0%，進而較佳為設為未達1.0%。 SnO2
成分可使用SnO、SnO2
、SnF2
、SnF4
等作為原料。 Sb2
O3
成分係於含有超過0%之情形時，可使玻璃澄清之任意成分。 另一方面，藉由將Sb2
O3
成分之含量設為1.0%以下，可使玻璃熔解時之過度之發泡不易發生，因此可使Sb2
O3
成分不易與熔解設備(尤其是Pt等貴金屬)合金化。因此，Sb2
O3
成分之含量較佳為以1.0%以下為上限，更佳為以未達0.5%為上限，進而較佳為以未達0.1%為上限。但於重視光學玻璃之環境方面之影響之情形時，亦可不含有Sb2
O3
成分。 Sb2
O3
成分可使用Sb2
O3
、Sb2
O5
、Na2
H2
Sb2
O7
・5H2
O等作為原料。 再者，使玻璃澄清之成分並不限定於上述之Sb2
O3
成分，可使用玻璃製造之領域中公知之澄清劑、或該等之組合。 SiO2
成分之含量相對於SiO2
成分及B2
O3
成分之合計量之比(莫耳比)較佳為未達0.95。藉此，可進一步提高玻璃之再加熱加壓成形性。因此，該莫耳比(SiO2
)/(SiO2
＋B2
O3
)較佳為設為未達0.95，更佳為設為未達0.90，進而較佳為設為未達0.85。 另一方面，該莫耳比(SiO2
)/(SiO2
＋B2
O3
)亦可較佳為將0.30設為下限，更佳為將0.50設為下限，進而較佳為將0.60設為下限。 Rn2
O成分(式中，Rn為選自由Li、Na、K所組成之群之1種以上)之含量之和(莫耳和)較佳為5.0%以上且40.0%以下。 尤其是藉由將該莫耳和設為5.0%以上，可提高玻璃原料之熔解性，且降低玻璃轉移點。因此，Rn2
O成分之合計含量亦可較佳為設為5.0%以上，更佳為設為超過10.0%，進而較佳為設為超過15.0%，進而較佳為設為超過17.0%。 另一方面，藉由將該莫耳和設為40.0%以下，可使玻璃之折射率不易降低，可減少玻璃形成時之失透。因此，Rn2
O成分之合計含量較佳為設為40.0%以下，更佳為設為未達35.0%，進而較佳為設為未達30.0%，進而較佳為設為未達24.0%。 RO成分(式中，R為選自由Mg、Ca、Sr、Ba所組成之群之1種以上)之含量之和(莫耳和)較佳為25.0%以下。藉此，可抑制阿貝數之上升，且可減少由該等成分之過量含有所引起之玻璃之失透。因此，RO成分之莫耳和較佳為設為25.0%以下，更佳為設為未達15.0%，進而較佳為設為未達10.0%，進而較佳為設為未達5.0%，進而較佳為設為未達2.5%。 Ln2
O3
成分(式中，Ln為選自由La、Gd、Y、Yb所組成之群之1種以上)之含量之和(莫耳和)較佳為20.0%以下。藉此，可減少玻璃之失透，抑制阿貝數之上升，且可降低材料成本。因此，Ln2
O3
成分之莫耳和較佳為設為20.0%以下，更佳為設為未達15.0%，進而較佳為設為未達10.0%，進而較佳為設為未達7.0%，進而較佳為設為未達5.0%，進而較佳為設為未達3.0%，進而較佳為設為未達1.0%。 Li2
O成分及Na2
O成分之合計量相對於Rn2
O成分(式中，Rn為選自由Li、Na、K所組成之群之1種以上)之合計量之比(莫耳比)較佳為0.75以上。藉此，可進一步提高玻璃之再加熱加壓成形性。因此，該莫耳比(Li2
O＋Na2
O)/(Rn2
O)較佳為將0.75設為下限，更佳為將0.88設為下限，進而較佳為將0.96設為下限。 再者，將該莫耳比(Li2
O＋Na2
O)/(Rn2
O)之上限設為1。 ＜關於不應含有之成分＞ 其次，對本發明之光學玻璃中不應含有之成分、及不佳為含有之成分加以說明。 可於無損本案發明之玻璃之特性之範圍內視需要添加其他之成分。但除Ti、Zr、Nb、W、La、Gd、Y、Yb、Lu以外之V、Cr、Mn、Fe、Co、Ni、Cu、Ag及Mo等各過渡金屬成分即便於分別單獨或複合含有少量之情形時，亦具有使玻璃發生著色而對可見光範圍之特定之波長產生吸收之性質，因此尤其是於使用可見光範圍之波長之光學玻璃中，較佳為實質上不含有。 又，PbO等鉛化合物及As2
O3
等砷化合物由於為環境負荷較高之成分，故而較理想為實質上不含有，即除不可避免之混入以外完全不含有。 進而，Th、Cd、Tl、Os、Be、及Se各成分近年存在作為有害之化學物資而控制使用之傾向，不僅玻璃之製造步驟，甚至加工步驟、及製品化後之處置均需要進行環境對策方面之措施。因此，於重視環境方面之影響之情形時，較佳為實質上不含有該等。 [製造方法] 本發明之光學玻璃例如係以如下方式製作。即，將上述原料以各成分成為特定之含量之範圍內之方式均勻混合，將所製作之混合物投入至鉑坩堝、石英坩堝或氧化鋁坩堝中，粗熔融後，放入至金坩堝、鉑坩堝、鉑合金坩堝或銥坩堝中，於1100～1400℃之溫度範圍內熔融3～5小時，攪拌使之均質化，進行消泡等後，降低至1000～1400℃之溫度，然後進行完工攪拌，去除脈理，澆鑄至模具中並進行緩冷，藉此製作。 此時，作為玻璃原料，較佳為使用熔解性較高者。藉此，可實現更低溫下之熔解、或更短時間之熔解，因此可提高玻璃之生產性，降低生產成本。又，由於減少成分之揮發或與坩堝等之反應，故而可容易獲得著色較少之玻璃。 ＜物性＞ 本發明之光學玻璃具有較高之折射率與特定之範圍之阿貝數。 本發明之光學玻璃之折射率(nd
)較佳為以1.62為下限，更佳為以1.63為下限，進而較佳為以1.64為下限。該折射率之上限亦可較佳為1.75，更佳為1.74，進而較佳為1.72，進而較佳為1.70，進而較佳為1.69。 本發明之光學玻璃之阿貝數(νd
)較佳為設為42以下，更佳為設為40以下，進而較佳為設為39以下，進而較佳為設為38以下。另一方面，本發明之光學玻璃之阿貝數(νd
)較佳為以30為下限，更佳為以32為下限，進而較佳為以34為下限。 具有此種折射率及阿貝數之本發明之光學玻璃於光學設計方面有用，尤其是可謀求較高之成像特性等，並且可謀求光學系統之小型化，因此可擴大光學設計之自由度。 此處，本發明之光學玻璃較佳為折射率(nd
)及阿貝數(νd
)滿足(‑0.012νd
＋2.04)≦nd
≦(-0.012νd
＋2.14)之關係。本發明所特定之組成之玻璃藉由折射率(nd
)及阿貝數(νd
)滿足該關係，可獲得更加不易產生失透之玻璃。 因此，本發明之光學玻璃較佳為折射率(nd
)及阿貝數(νd
)滿足nd≧(‑0.012νd
＋2.04)之關係，更佳為滿足nd
≧(-0.012νd
＋2.05)之關係，進而較佳為滿足nd
≧(-0.012νd
＋2.06)之關係。 另一方面，本發明之光學玻璃較佳為折射率(nd
)及阿貝數(νd
)滿足nd
≦(-0.012νd
＋2.14)之關係，更佳為滿足nd
≦(-0.012νd
＋2.13)之關係，進而較佳為滿足nd
≦(-0.012νd
＋2.12)之關係。 本發明之光學玻璃具有較低之部分分散比(θg，F)。 更具體而言，本發明之光學玻璃之部分分散比(θg，F)較佳為以0.594為上限，更佳為以0.590為上限，進而較佳為以0.586為上限。該部分分散比(θg，F)之下限亦可較佳為0.570，更佳為0.573，進而較佳為0.575。 又，本發明之光學玻璃之部分分散比(θg，F)較佳為與阿貝數(νd
)之間滿足(-0.00162×νd
＋0.630)≦(θg，F)≦(-0.00162×νd
＋0.652)之關係。 藉此，可獲得具有較低之部分分散比(θg，F)之光學玻璃，故而可將由該光學玻璃所形成之光學元件用於降低光學系統之色像差。 因此，本發明之光學玻璃較佳為部分分散比(θg，F)及阿貝數(νd
)滿足θg，F≧(-0.00162×νd
＋0.630)之關係，更佳為滿足θg，F≧(‑0.00162×νd
＋0.632)之關係，進而較佳為滿足θg，F≧(-0.00162×νd
＋0.634)之關係。 另一方面，本發明之光學玻璃較佳為部分分散比(θg，F)及阿貝數(νd
)滿足θg，F≦(-0.00162×νd
＋0.652)之關係，更佳為滿足θg，F≦(‑0.00162×νd
＋0.650)之關係，進而較佳為滿足θg，F≦(-0.00162×νd
＋0.648)之關係，進而較佳為滿足θg，F≦(-0.00162×νd
＋0.646)之關係，進而較佳為滿足θg，F≦(-0.00162×νd
＋0.643)之關係。 再者，由上述部分分散比(θg，F)及阿貝數(νd
)之關係式表示：藉由使用與正規線為相同斜率之直線規定該等之關係，可獲得部分分散比(θg，F)較一般之玻璃小之玻璃。 本發明之光學玻璃較佳為比重較小。更具體而言，本發明之光學玻璃之比重較佳為3.50[g/cm3
]以下。藉此，由於光學元件或使用其之光學設備之質量下降，故而可有助於光學設備之輕量化。因此，本發明之光學玻璃之比重較佳為以3.50為上限，更佳為以3.30為上限，進而較佳為以3.10為上限。再者，本發明之光學玻璃之比重多數情況下大約為2.50以上，更詳細而言為2.70以上，進而詳細而言為2.80以上。 本發明之光學玻璃之比重係基於日本光學玻璃工業會標準JOGIS05-1975「光學玻璃之比重之測定方法」而測定。 本發明之光學玻璃較佳為具有650℃以下之玻璃轉移點。藉此，由於玻璃於更低之溫度下發生軟化，故而可以更低之溫度將玻璃模壓成形。又，亦可減少模壓成形所使用之模具之氧化，謀求模具之長壽化。因此，本發明之光學玻璃之玻璃轉移點較佳為以650℃為上限，更佳為以620℃為上限，進而較佳為以600℃為上限。 再者，本發明之光學玻璃之玻璃轉移點之下限並無特別限定，本發明之光學玻璃之玻璃轉移點亦可較佳為以460℃為下限，更佳為以480℃為下限，進而較佳為以500℃為下限。 本發明之光學玻璃較佳為具有700℃以下之屈服點(At)。屈服點係與玻璃轉移點同樣地表示玻璃之軟化性之指標之一，係表示接近加壓成形溫度之溫度之指標。因此，藉由使用屈服點為700℃以下之玻璃，可實現更低之溫度下之加壓成形，因此可更容易地進行加壓成形。因此，本發明之光學玻璃之屈服點較佳為以700℃為上限，更佳為以680℃為上限，最佳為以660℃為上限。 再者，本發明之光學玻璃之屈服點並無特別限制，但亦可較佳為以500℃為下限，更佳為以530℃為下限，進而較佳為以560℃為下限。 本發明之光學玻璃較佳為平均線膨脹係數(α)較小。本發明之光學玻璃之平均線膨脹係數尤其是較佳為以120×10-7
K-1
為上限，更佳為以110×10-7
K-1
為上限，進而較佳為以100×10-7
K-1
為上限。藉此，於以成形模具將光學玻璃加壓成形時，由玻璃之溫度變化所引起之膨脹或收縮之總量減少。因此，可使光學玻璃於加壓成形時不易破裂，可提高光學元件之生產性。 本發明之光學玻璃較佳為再加熱加壓成形性良好。更具體而言，本發明之光學玻璃較佳為即便於再加熱試驗(模具陷入試驗)之前後亦不會產生失透及乳白。藉此，由於即便由假設再加熱加壓加工之再加熱試驗亦不易產生失透及著色，故而不易失去玻璃之光線透過率，可容易對玻璃進行以再加熱加壓加工為代表之再加熱處理。即，由於可藉由加壓成形來製作形狀複雜之光學元件，故而可實現製造成本較低，且生產性較高之光學元件製造。 此處，再加熱試驗(模具陷入試驗)可利用以下方法進行：將15 mm×15 mm×30 mm之試片置於凹型耐火物上，放入至電爐中進行再加熱，自常溫升溫150分鐘至較各試樣之屈服點(At)高出80℃～150℃之溫度(陷入至耐火物之溫度)，於該溫度下保溫30分鐘後，冷卻至常溫，取出至爐外，以可於內部觀察之方式，將對向之2面研磨至厚度10 mm後，對研磨過之玻璃試樣進行目視觀察。 再者，再加熱試驗(模具陷入試驗)之前後之失透及乳白之有無例如可以目視進行確認，「未產生失透及乳白」係指例如再加熱試驗(模具陷入試驗)後之試片之波長587.56 nm之光線(d射線)之透過率除以再加熱試驗前之試片之d射線之透過率所得之值大約為0.80以上。 本發明之光學玻璃較佳為具有較高之化學耐久性。更具體而言，本發明之光學玻璃較佳為具有較高之耐水性或耐酸性。藉此，於對光學玻璃進行研磨加工時，減少由洗淨液或研磨液所引起之玻璃之污濁，故而可使研磨加工更容易進行。 再者，光學玻璃之耐水性及耐酸性係指於基於日本光學玻璃工業會標準「光學玻璃之化學耐久性之測定方法」JOGIS06-2008之化學耐久性(耐水性、耐酸性)中，較佳為1～3級，更佳為1～2級，進而較佳為1級。 本發明之光學玻璃較佳為於製作玻璃時不易產生失透。藉此，由於由製作玻璃時之玻璃之結晶化等所引起之透過率之降低被抑制，故而可將該光學玻璃較佳地用於透鏡等使可見光透過之光學元件。再者，作為表示難以產生製作玻璃時之失透之尺度，例如可列舉液相溫度較低。 [預成形材及光學元件] 可自所製作之光學玻璃使用例如再加熱加壓成形或精密加壓成形等模壓成形之方法，製作玻璃成形體。即，可自光學玻璃製作模壓成形用之預成形材，對該預成形材進行再加熱加壓成形後，進行研磨加工而製作玻璃成形體；或例如進行研磨加工，對所製作之預成形材進行精密加壓成形而製作玻璃成形體。再者，製作玻璃成形體之方法並不限定於該等方法。 如此所製作之玻璃成形體對各種光學元件有用，但其中尤其是較佳為用於透鏡或稜鏡等光學元件之用途。藉此，設置有光學元件之光學系統於透射光下之由色像差所引起之顏色之模糊減少。因此，於將該光學元件用於相機之情形時，可更準確地表現拍攝對象物，將該光學元件用於投影儀之情形時，可更高清地投影所需之影像。 [實施例] 將本發明之實施例(No.1～No.29)之組成、及折射率(nd
)、阿貝數(νd
)、部分分散比(θg，F)、玻璃轉移點(Tg)、屈服點(At)、平均線膨脹係數(α)、比重、以及再加熱試驗(模具陷入試驗)之結果示於表1～表5中。再者，以下之實施例僅為例示之目的，並非僅限定於該等實施例。 作為各成分之原料，實施例之玻璃均係選定各相應之氧化物、氫氧化物、碳酸鹽、硝酸鹽、氟化物、氫氧化物、偏磷酸化合物等通常用於光學玻璃之高純度之原料，以成為表中所示之各實施例及比較例之組成之比率之方式稱量並均勻混合後，投入至鉑坩堝中，根據玻璃原料之熔解難易度，利用電爐於1100～1400℃之溫度範圍內熔解3～5小時，攪拌使之均質化，進行消泡等後，將溫度降至1000～1400℃，攪拌使之均質化後澆鑄至模具中，進行緩冷，而製作玻璃。 實施例之玻璃之折射率(nd
)、阿貝數(νd
)及部分分散比(θg，F)係基於日本光學玻璃工業會標準JOGIS01-2003而測定。 繼而，根據所獲得之折射率(nd
)及阿貝數(νd
)之值，求出關係式(nd
＝-a×νd
＋b)中之斜率a為0.012時之截距b。 又，根據所獲得之阿貝數(νd
)及部分分散比(θg，F)之值，求出關係式(θg，F＝-a'×νd
＋b')中之斜率a'為0.00162時之截距b'。 再者，本測定中所使用之玻璃係使用將緩冷降溫速度設為-25℃/hr，於緩冷爐中進行過處理者。 實施例之玻璃之玻璃轉移點(Tg)及屈服點(At)係按照日本光學玻璃工業會標準JOGIS08-2003「光學玻璃之熱膨脹之測定方法」，由藉由測定溫度與試樣之伸長之關係而獲得之熱膨脹曲線而求出。 實施例之玻璃之平均線膨脹係數(α)係按照日本光學玻璃工業會標準JOGIS08-2003「光學玻璃之熱膨脹之測定方法」，求出100～300℃之平均線膨脹係數。 實施例之玻璃之比重係基於日本光學玻璃工業會標準JOGIS05-1975「光學玻璃之比重之測定方法」而測定。 又，關於實施例之玻璃，目視確認再加熱試驗(模具陷入試驗)之前後之失透及乳白之有無。此處，再加熱試驗後之前後之失透及乳白之確認係藉由如下方式進行：將15 mm×15 mm×30 mm之試片置於凹型耐火物上，放入至電爐中再加熱至再加熱溫度，於該溫度下保溫30分鐘後，冷卻至常溫，取出至爐外，以可於內部進行觀察之方式，將對向之2面研磨至厚度10 mm後，目視觀察研磨過之玻璃試樣之失透及乳白之有無。此時，將如下玻璃之「模具陷入試驗」記為「○」：對試片將再加熱溫度設為(At＋80℃～130℃)保溫時，未出現失透及乳白，並且對另一試片將再加熱溫度設為(At＋超過130℃～150℃)保溫時，亦未出現失透及乳白。又，將如下玻璃之「模具陷入試驗」記為「△」：對試片將再加熱溫度設為(At＋80℃～130℃)保溫時未出現失透及乳白，但對另一試片將再加熱溫度設為(At＋超過130℃～150℃)保溫時，出現失透或乳白。又，將如下玻璃之「模具陷入試驗」記為「×」：即便對試片將再加熱溫度設為(At＋80℃～90℃)保溫時，亦出現失透或乳白。 [表1]
[表2]
[表3]
[表4]
[表5]
如該等表所示，實施例(No.1～No.29)之光學玻璃之部分分散比(θg，F)為0.594以下，為所需之範圍內。 此處，本發明之實施例之光學玻璃之部分分散比(θg，F)及阿貝數(νd
)滿足(-0.00162×νd
＋0.630)≦(θg，F)≦(-0.00162×νd
＋0.652)之關係，更詳細而言滿足(θg，F)≦(-0.00162×νd
＋0.651)之關係。並且，本案之實施例之玻璃之部分分散比(θg，F)與阿貝數(νd
)之關係成為如圖2所示。 因此，明確可知本發明之實施例之光學玻璃具有較小之部分分散比(θg，F)。 本發明之實施例之光學玻璃之折射率(nd
)均為1.62以上，更詳細而言為1.64以上，且該折射率(nd
)為1.75以下，為所需之範圍內。 又，本發明之實施例之光學玻璃之阿貝數(νd
)均為30以上，更詳細而言為34以上，且該阿貝數(νd
)為42以下，更詳細而言為41以下，為所需之範圍內。 此處，本發明之實施例之光學玻璃之折射率(nd
)及阿貝數(νd
)滿足(‑0.012νd
＋2.04)≦nd
≦(-0.012νd
＋2.14)之關係，更詳細而言滿足(‑0.012νd
＋2.08)≦nd
≦(-0.012νd
＋2.13)之關係。並且，本案之實施例之玻璃之折射率(nd
)及阿貝數(νd
)之關係成為如圖3所示。 因此，明確可知實施例之光學玻璃係折射率(nd
)及阿貝數(νd
)在所需之範圍內，且部分分散比(θg，F)較小之光學玻璃。 其中，尤其是實施例(No.1～No.8)之光學玻璃於進行再加熱試驗(模具陷入試驗)之前後均不易產生失透及乳白。另一方面，實施例(No.9～No.10)之光學玻璃於較試樣之屈服點(At)高出80℃～150℃之溫度範圍中之至少一部分溫度範圍內產生失透或乳白。因此，實施例(No.1～No.8)之光學玻璃與實施例(No.9～No.10)相比，不易產生由再加熱所導致之失透或乳白，故而推測其具有較高之再加熱加壓成形性。 此外，實施例之光學玻璃之比重均為3.50以下，更詳細而言為3.30以下，為所需之範圍內。 又，實施例之光學玻璃之玻璃轉移點為650℃以下，更詳細而言為630℃以下。又，實施例之光學玻璃之屈服點均為700℃以下，為所需之範圍內。由該等可推測：可以更低之溫度將玻璃模壓成形。 又，實施例之光學玻璃之平均線膨脹係數(α)為120×10-7
K-1
以下，更詳細而言為110×10-7
K-1
以下，為所需之範圍內。 進而，於使用實施例之光學玻璃形成透鏡預成形材，並對該透鏡預成形材進行模壓成形時，可不產生失透或乳白而加工為各種透鏡形狀。 以上，出於例示之目的對本發明詳細地進行了說明，但應理解本實施例僅為例示之目的，業者可不脫離本發明之思想及範圍而完成多種改變。The optical glass of the present invention contains SiO% and contains SiO 2 Composition 20.0 to 65.0%, Nb 2 O 5 Composition 1.0 to 25.0% and Na 2 The O component is 1.0 to 35.0%, and has a refractive index of 1.62 or more and 1.75 or less (n). d ), the Abbe number of 30 or more and 42 or less (ν d ), and a partial dispersion ratio (θg, F) of 0.594 or less. Can contain SiO 2 Composition and Nb 2 O 5 In the glass of the composition, a glass having a higher refractive index or a lower Abbe number (higher dispersion) and a lower partial dispersion ratio in a desired range is obtained. Therefore, a higher refractive index is obtained (n d ) and lower Abbe number (ν d ), and the partial dispersion ratio (θg, F) is small, and is an optical glass useful for reducing chromatic aberration of an optical system. Further, an optical glass suitable for reheating and press forming due to a decrease in devitrification upon reheating of the glass can be obtained. Further, it is possible to obtain an optical glass which contributes to the weight reduction of the optical device due to the small specific gravity, and which can lower the heating temperature at the time of reheating and press forming due to the lower glass transition point. Hereinafter, the embodiment of the optical glass of the present invention will be described in detail, but the present invention is not limited to the following embodiments, and can be appropriately modified and implemented within the scope of the object of the present invention. In addition, the description of the place where the description is repeated is appropriately omitted, but the present invention is not limited. [Glass component] Hereinafter, the composition range of each component constituting the optical glass of the present invention will be described. In the present specification, the content of each component is expressed by the mole % of the total moles of the glass in terms of oxide, unless otherwise specified. Here, the "oxide-converting composition" means a composition in which an oxide, a composite salt, and a metal fluoride which are assumed to be used as a raw material of the glass constituent component of the present invention are equal to the case where all of the oxides are decomposed into oxides upon melting. The total number of moles of the produced oxide was set to 100 mol% to represent each component contained in the glass. <About essential components, optional components> SiO 2 The component promotes stable formation of the glass and reduces the amount of devitrification (production of crystals) which is unsatisfactory as the optical glass. Especially by SiO 2 When the content of the component is 20.0% or more, the partial dispersion ratio can be not greatly increased to reduce devitrification. Moreover, by this, devitrification or coloring at the time of reheating can be reduced. Therefore, SiO 2 The content of the component is preferably 20.0% or more, more preferably more than 30.0%, further preferably more than 35.0%, more preferably more than 40.0%, and still more preferably more than 43.0%. Further preferably, it is set to exceed 45.0%. On the other hand, by SiO 2 When the content of the component is 65.0% or less, the refractive index is not easily lowered, so that a desired high refractive index can be easily obtained, and an increase in the partial dispersion ratio can be suppressed. Further, by this, it is possible to suppress a decrease in the meltability of the glass raw material. Therefore, SiO 2 The content of the component is preferably 65.0% or less, more preferably less than 60.0%, still more preferably less than 58.0%, and still more preferably less than 55.0%. SiO 2 Ingredients can use SiO 2 , K 2 SiF 6 Na 2 SiF 6 Etc. as a raw material. Nb 2 O 5 By containing 1.0% or more, the composition can increase the refractive index of the glass, and can reduce the Abbe number and the partial dispersion ratio. Therefore, Nb 2 O 5 The content of the component is preferably 1.0% or more, more preferably more than 3.0%, still more preferably more than 5.0%, and still more preferably more than 7.0%. On the other hand, by using Nb 2 O 5 When the content of the component is 25.0% or less, the material cost of the glass can be lowered. Moreover, the increase in the melting temperature at the time of glass production can be suppressed, and the reduction by Nb can be suppressed. 2 O 5 Devitrification caused by the excessive content of ingredients. Therefore, Nb 2 O 5 The content of the component is preferably 25.0% or less, more preferably less than 20.0%, still more preferably less than 15.0%, still more preferably less than 11.0%, and further preferably set to Less than 10.0%. Nb 2 O 5 Ingredients can use Nb 2 O 5 Etc. as a raw material. Na 2 The O component is an essential component which can reduce the partial dispersion ratio of the glass, increase the reheating and pressurizing property, lower the glass transition point, and improve the meltability of the glass raw material by containing 1.0% or more. Therefore, Na 2 The content of the O component is preferably 1.0% or more, more preferably more than 5.0%, still more preferably more than 8.0%, still more preferably more than 11.0%, and still more preferably more than 13.0. % is further preferably set to exceed 15.0%. On the other hand, by Na 2 When the content of the O component is 35.0% or less, the decrease in the refractive index of the glass can be suppressed, the chemical durability can be prevented from being deteriorated, and the devitrification caused by the excessive content can be reduced. Therefore, Na 2 The content of the O component is preferably 35.0% or less, more preferably less than 30.0%, still more preferably less than 25.0%, and still more preferably less than 23.0%. Na 2 O component can use Na 2 CO 3 NaNO 3 , NaF, Na 2 SiF 6 Etc. as a raw material. SiO 2 Composition, Nb 2 O 5 Composition and Li 2 The total amount of the O components (molar sum) is preferably 25.0% or more and 70.0% or less. In particular, by setting the total amount to 25.0% or more, the reheating and pressurizing property of the glass can be improved. Therefore, Moer and (SiO 2 +Nb 2 O 5 +Li 2 O) is preferably 25.0% or more, more preferably more than 30.0%, further preferably more than 40.0%, further preferably more than 50.0%, and more preferably more than 54.0%. More preferably, it is 58.05% or more. On the other hand, by setting the total amount to 70.0% or less, the devitrification of the glass can be reduced. Therefore, Moer and (SiO 2 +Nb 2 O 5 +Li 2 O) Preferably, 70.0% is made the upper limit, more preferably 68.0% is set as the upper limit, and further preferably 65.0% is set as the upper limit. B 2 O 3 When the content is more than 0%, the glass can be stably formed to reduce devitrification, and the composition of the glass raw material can be improved. Therefore, B 2 O 3 The content of the component may preferably be more than 0%, more preferably more than 1.0%, still more preferably more than 2.0%, still more preferably more than 4.0%, and still more preferably more than 6.0% is further preferably more than 7.0%, more preferably more than 10.0%, and still more preferably more than 12.0%. On the other hand, by B 2 O 3 When the content of the component is 30.0% or less, the decrease in the refractive index or the increase in the Abbe number can be suppressed, and the increase in the partial dispersion ratio can be suppressed. Therefore, B 2 O 3 The content of the component is preferably 30.0% or less, more preferably less than 25.0%, still more preferably less than 20.0%, and still more preferably less than 18.0%. B 2 O 3 Ingredients can be used H 3 BO 3 Na 2 B 4 O 7 Na 2 B 4 O 7 ・10H 2 O, BPO 4 Etc. as a raw material. ZrO 2 When the content is more than 0%, the refractive index of the glass can be increased, the Abbe number can be lowered, the partial dispersion ratio can be lowered, and any component of devitrification can be reduced. Moreover, by this, devitrification or coloring at the time of reheating can be reduced. Therefore, ZrO 2 The content of the component may preferably be more than 0%, more preferably more than 0.5%, still more preferably more than 1.0%, still more preferably more than 3.0%, and still more preferably more than 5.0. %. On the other hand, by ZrO 2 When the content of the component is 20.0% or less, devitrification can be reduced, and a more homogeneous glass can be easily obtained. Therefore, ZrO 2 The content of the component is preferably 20.0% or less, more preferably less than 15.0%, still more preferably less than 12.0%, still more preferably less than 10.0%, and further preferably set to be less than 10.0%. Not up to 9.0%. ZrO 2 Ingredients can use ZrO 2 ZrF 4 Etc. as a raw material. Li 2 When the O component is contained in an amount of more than 0%, the partial dispersion ratio of the glass can be lowered, the reheating and pressurizing property can be improved, the glass transition point can be lowered, and any component which can improve the meltability of the glass raw material can be obtained. Therefore, Li 2 The content of the O component may preferably be more than 0%, more preferably more than 0.3%, still more preferably more than 0.5%. On the other hand, by using Li 2 When the content of the O component is 20.0% or less, the decrease in the refractive index can be suppressed, the chemical durability is hardly deteriorated, and the devitrification caused by the excessive content can be reduced. Therefore, Li 2 The content of the O component is preferably 20.0% or less, more preferably less than 15.0%, still more preferably less than 12.0%, and still more preferably less than 10.0%. Li 2 O component can use Li 2 CO 3 LiNO 3 , LiF, etc. as raw materials. TiO 2 When the composition is contained in an amount exceeding 0%, the refractive index can be increased, the Abbe number can be lowered, and any component of devitrification can be reduced. On the other hand, by TiO 2 When the content of the component is 15.0% or less, the color of the glass can be reduced, and the internal transmittance can be improved. Further, by this, the partial dispersion ratio is less likely to rise, so that the desired lower partial dispersion ratio can be easily obtained. Therefore, TiO 2 The content of the component is preferably 15.0% or less, more preferably less than 12.0%, still more preferably less than 10.0%, still more preferably less than 5.0%, and further preferably set to Less than 3.0%. TiO 2 Ingredients can use TiO 2 Etc. as a raw material. K 2 When the O component is contained in an amount exceeding 0%, the refractive index can be lowered, the meltability of the glass raw material can be improved, and any component of the glass transition point can be lowered. On the other hand, by K 2 When the content of the O component is 10.0% or less, the increase in the partial dispersion ratio can be suppressed, the devitrification can be reduced, and the chemical durability can be prevented from being deteriorated. Further, it is possible to suppress a decrease in reheating press formability. Therefore, K 2 The content of the O component is preferably 10.0% or less, more preferably less than 5.0%, still more preferably less than 3.0%, still more preferably less than 1.5%, and further preferably It is less than 0.5%. K 2 O component can use K 2 CO 3 KNO 3 , KF, KHF 2 , K 2 SiF 6 Etc. as a raw material. When the MgO component is contained in an amount exceeding 0%, any component of the melting temperature of the glass can be lowered. On the other hand, by setting the content of the MgO component to 10.0% or less, it is possible to suppress a decrease in the refractive index or an increase in the Abbe number, and it is possible to reduce devitrification. Therefore, the content of the MgO component is preferably 10.0% or less, more preferably less than 5.0%, still more preferably less than 3.0%, and still more preferably less than 1.0%. MgO, MgCO, MgCO, MgCO 3 , MgF 2 Etc. as a raw material. When the CaO component is contained in an amount exceeding 0%, the material cost of the glass can be lowered, and the devitrification can be reduced, and any component which can melt the glass raw material can be improved. On the other hand, by setting the content of the CaO component to 15.0% or less, it is possible to suppress a decrease in the refractive index or an increase in the Abbe number, suppress an increase in the partial dispersion ratio, and reduce devitrification. Therefore, the content of the CaO component is preferably 15.0% or less, more preferably less than 10.0%, still more preferably less than 5.0%, and still more preferably less than 2.5%. CaO ingredients can use CaCO 3 CaF 2 Etc. as a raw material. When the SrO component is contained in an amount exceeding 0%, the devitrification of the glass can be reduced, and any component of the refractive index can be increased. In particular, by setting the content of the SrO component to 15.0% or less, it is possible to suppress an increase in the Abbe number and to suppress deterioration in chemical durability. Therefore, the content of the SrO component is preferably 15.0% or less, more preferably less than 10.0%, still more preferably less than 5.0%, still more preferably less than 3.0%, and further preferably Set to less than 1.0%. SrO component can use Sr (NO 3 ) 2 , SrF 2 Etc. as a raw material. When the BaO component is contained in an amount exceeding 0%, the devitrification of the glass can be reduced, the refractive index can be increased, the meltability of the glass raw material can be improved, and any component of the material cost of the glass can be reduced as compared with other alkaline earth components. Further, it is also a component which can suppress a decrease in reheating and press formability. On the other hand, by setting the content of the BaO component to 25.0% or less, it is possible to suppress an increase in the Abbe number and suppress deterioration of chemical durability or devitrification. Therefore, the content of the BaO component is preferably 25.0% or less, more preferably less than 15.0%, still more preferably less than 10.0%, and still more preferably less than 5.0%. BaCO ingredients can use BaCO 3 , Ba(NO 3 ) 2 Etc. as a raw material. La 2 O 3 Ingredients, Gd 2 O 3 Composition, Y 2 O 3 Ingredients and Yb 2 O 3 The component is an element which can increase the refractive index by at least any of more than 0% and lower the partial dispersion ratio. On the other hand, by La 2 O 3 When the content of the component is 15.0% or less, the increase in the Abbe number can be suppressed, the specific gravity can be reduced, and devitrification can be reduced. So La 2 O 3 The content of the component is preferably 15.0% or less, more preferably less than 10.0%, still more preferably less than 5.0%, still more preferably less than 3.0%, and further preferably set to Less than 1.0%. Again, by Y 2 O 3 When the content of the component is 20.0% or less, the increase in the Abbe number can be suppressed, the specific gravity can be reduced, and the devitrification can be reduced. Therefore, Y 2 O 3 The content of the component is preferably 20.0% or less, more preferably less than 10.0%, still more preferably less than 5.0%, and still more preferably less than 3.0%. Again, by putting Gd 2 O 3 Ingredients and Yb 2 O 3 When the content of each component is 10.0% or less, the increase in the Abbe number can be suppressed, the specific gravity can be reduced, the devitrification can be reduced, and the material cost can be reduced. Therefore, Gd 2 O 3 Ingredients and Yb 2 O 3 The content of each component is preferably 10.0% or less, more preferably less than 5.0%, still more preferably less than 3.0%, and still more preferably less than 1.0%. La 2 O 3 Ingredients, Gd 2 O 3 Composition, Y 2 O 3 Ingredients and Yb 2 O 3 Ingredients can be used La 2 O 3 La(NO 3 ) 3 ・XH 2 O (X is an arbitrary integer), Y 2 O 3 YF 3 Gd 2 O 3 GdF 3 , Yb 2 O 3 Etc. as a raw material. P 2 O 5 When the component is contained in an amount exceeding 0%, the component which devitrifies the glass can be reduced. On the other hand, by putting P 2 O 5 The content of the component is set to 10.0% or less, which can be reduced by P 2 O 5 Devitrification caused by the excessive content of ingredients. Therefore, P 2 O 5 The content of the component is preferably 10.0% or less, more preferably less than 5.0%, still more preferably less than 3.0%, and still more preferably less than 1.0%. P 2 O 5 Ingredients can use Al (PO 3 ) 3 Ca(PO 3 ) 2 , Ba (PO 3 ) 2 BPO 4 , H 3 PO 4 Etc. as a raw material. GeO 2 When the composition is contained in an amount exceeding 0%, the refractive index can be increased and any component of devitrification can be reduced. On the other hand, by using GeO 2 The content of the component is set to 10.0% or less due to the expensive GeO 2 The use of ingredients is reduced, so the material cost of the glass can be reduced. Therefore, GeO 2 The content of the component is preferably 10.0% or less, more preferably less than 5.0%, and still more preferably less than 1.0%. GeO 2 GeO can be used as a component 2 Etc. as a raw material. Al 2 O 3 Composition and Ga 2 O 3 When the component contains at least 0%, it can improve chemical durability and reduce any component of devitrification of the glass. On the other hand, by Al 2 O 3 When the content of the component is 15.0% or less, devitrification caused by excessive content can be reduced. Therefore, Al 2 O 3 The content of the component is preferably 15.0% or less, more preferably less than 8.0%, still more preferably less than 5.0%, and still more preferably less than 3.0%. Again, by placing Ga 2 O 3 When the content of the component is 10.0% or less, devitrification caused by excessive content can be reduced. Therefore, Ga 2 O 3 The content of the component is preferably 10.0% or less, more preferably less than 5.0%, and still more preferably less than 3.0%. Al 2 O 3 Composition and Ga 2 O 3 Ingredients can use Al 2 O 3 , Al(OH) 3 AlF 3 Ga 2 O 3 Ga(OH) 3 Etc. as a raw material. Ta 2 O 5 When the content is more than 0%, the refractive index can be increased, the partial dispersion ratio can be lowered, and any component which devitrifies the glass can be reduced. On the other hand, by Ta 2 O 5 The content of the component is set to 10.0% or less because of Ta as a rare mineral resource. 2 O 5 The use amount of the component is reduced, and the glass is easily melted at a lower temperature, so that the production cost of the glass can be reduced. Also, by this, it can be reduced by Ta 2 O 5 The excess of the ingredients contains the devitrification of the glass caused, or an increase in the Abbe number. Therefore, Ta 2 O 5 The content of the component is preferably 10.0% or less, more preferably less than 5.0%, still more preferably less than 3.0%, and still more preferably less than 1.0%. Especially in terms of reducing the material cost of glass, Ta can also be used. 2 O 5 The content of the ingredients was set to be less than 0.1%. Ta 2 O 5 Ingredients can use Ta 2 O 5 Etc. as a raw material. WO 3 When the content is more than 0%, the refractive index can be increased, the Abbe number can be lowered, the devitrification of the glass can be reduced, and any component which can improve the meltability of the glass raw material can be obtained. On the other hand, by putting WO 3 When the content of the component is 10.0% or less, it is difficult to increase the partial dispersion ratio of the glass, and the color of the glass can be reduced, and the internal transmittance can be improved. Therefore, WO 3 The content of the component is preferably 10.0% or less, more preferably less than 5.0%, still more preferably less than 3.0%, and still more preferably less than 1.0%. WO 3 Ingredients can use WO 3 Etc. as a raw material. Bi 2 O 3 When the content is more than 0%, the refractive index can be increased, the Abbe number can be lowered, and any component of the glass transition point can be lowered. On the other hand, by Bi 2 O 3 When the content of the component is 10.0% or less, the partial dispersion ratio is less likely to rise, and the color of the glass can be reduced, and the internal transmittance can be improved. Therefore, Bi 2 O 3 The content of the component is preferably 10.0% or less, more preferably less than 5.0%, still more preferably less than 3.0%, and still more preferably less than 1.0%. Bi 2 O 3 Ingredients can use Bi 2 O 3 Etc. as a raw material. When the ZnO component is contained in an amount exceeding 0%, the devitrification of the glass can be reduced, the partial dispersion ratio can be lowered, and any component of the glass transition point can be lowered. On the other hand, by setting the content of the ZnO component to 20.0% or less, devitrification or coloring at the time of reheating of the glass can be reduced, and chemical durability can be improved. Therefore, the content of the ZnO component is preferably 20.0% or less, more preferably less than 10.0%, still more preferably less than 5.0%, and still more preferably less than 3.0%. ZnO, ZnF can be used for ZnO 2 Etc. as a raw material. TeO 2 When the content is more than 0%, the refractive index can be increased, the partial dispersion ratio can be lowered, and any component of the glass transition point can be lowered. On the other hand, by using TeO 2 When the content of the component is 10.0% or less, the color of the glass can be reduced, and the internal transmittance can be improved. Also, by reducing expensive TeO 2 The use of ingredients allows for a glass with a lower material cost. Therefore, TeO 2 The content of the component is preferably 10.0% or less, more preferably less than 5.0%, still more preferably less than 3.0%, and still more preferably less than 1.0%. TeO 2 Ingredients can use TeO 2 Etc. as a raw material. SnO 2 The component is any component which clarifies (defoams) the molten glass when it contains more than 0%. On the other hand, by using SnO 2 When the content of the component is 5.0% or less, the coloration of the glass caused by the reduction of the molten glass or the devitrification of the glass is less likely to occur. Also, due to SnO 2 Since the alloying of the components and the melting equipment (especially a precious metal such as Pt) is lowered, the life of the melting equipment can be increased. Therefore, SnO 2 The content of the component is preferably 5.0% or less, more preferably less than 3.0%, and still more preferably less than 1.0%. SnO 2 Ingredients can use SnO, SnO 2 , SnF 2 , SnF 4 Etc. as a raw material. Sb 2 O 3 The ingredient is any component which clarifies the glass when it contains more than 0%. On the other hand, by Sb 2 O 3 When the content of the component is 1.0% or less, excessive foaming during melting of the glass is less likely to occur, so that Sb can be made. 2 O 3 The composition is not easily alloyed with the melting equipment (especially precious metals such as Pt). Therefore, Sb 2 O 3 The content of the component is preferably an upper limit of 1.0% or less, more preferably an upper limit of less than 0.5%, and still more preferably an upper limit of less than 0.1%. However, when it is important to pay attention to the environmental aspects of optical glass, it may not contain Sb. 2 O 3 ingredient. Sb 2 O 3 Ingredients can use Sb 2 O 3 , Sb 2 O 5 Na 2 H 2 Sb 2 O 7 ・5H 2 O or the like as a raw material. Furthermore, the component for clarifying the glass is not limited to the above Sb. 2 O 3 As the ingredient, a clarifier known in the field of glass production, or a combination thereof may be used. SiO 2 The content of the component relative to SiO 2 Composition and B 2 O 3 The ratio of the total amount of the components (mol ratio) is preferably less than 0.95. Thereby, the reheating and press formability of the glass can be further improved. Therefore, the molar ratio (SiO 2 ) / (SiO 2 +B 2 O 3 It is preferably set to be less than 0.95, more preferably set to less than 0.90, and further preferably set to less than 0.85. On the other hand, the molar ratio (SiO 2 ) / (SiO 2 +B 2 O 3 It is also preferable to set 0.30 as the lower limit, more preferably 0.50 as the lower limit, and further preferably 0.60 as the lower limit. Rn 2 The sum (molar sum) of the content of the O component (wherein Rn is one or more selected from the group consisting of Li, Na, and K) is preferably 5.0% or more and 40.0% or less. In particular, by setting the molar amount to 5.0% or more, the meltability of the glass raw material can be improved, and the glass transition point can be lowered. Therefore, Rn 2 The total content of the O components is preferably 5.0% or more, more preferably more than 10.0%, still more preferably more than 15.0%, and still more preferably more than 17.0%. On the other hand, by setting the molar amount to 40.0% or less, the refractive index of the glass can be hardly lowered, and devitrification at the time of glass formation can be reduced. Therefore, Rn 2 The total content of the O components is preferably 40.0% or less, more preferably less than 35.0%, still more preferably less than 30.0%, and still more preferably less than 24.0%. The sum of the contents of the RO component (wherein R is one or more selected from the group consisting of Mg, Ca, Sr, and Ba) (mole sum) is preferably 25.0% or less. Thereby, the increase in the Abbe number can be suppressed, and the devitrification of the glass caused by the excessive content of the components can be reduced. Therefore, the molar content of the RO component is preferably 25.0% or less, more preferably less than 15.0%, further preferably less than 10.0%, and further preferably less than 5.0%, and further preferably less than 5.0%. It is preferably set to less than 2.5%. Ln 2 O 3 The sum of the contents (in the formula, Ln is one or more selected from the group consisting of La, Gd, Y, and Yb) (molar) is preferably 20.0% or less. Thereby, the devitrification of the glass can be reduced, the increase in the Abbe number can be suppressed, and the material cost can be reduced. Therefore, Ln 2 O 3 The molar content of the component is preferably 20.0% or less, more preferably less than 15.0%, still more preferably less than 10.0%, still more preferably less than 7.0%, and further preferably It is set to be less than 5.0%, more preferably set to less than 3.0%, and further preferably set to less than 1.0%. Li 2 O composition and Na 2 The total amount of O components is relative to Rn 2 The ratio (mol ratio) of the total amount of the O component (wherein Rn is one or more selected from the group consisting of Li, Na, and K) is preferably 0.75 or more. Thereby, the reheating and press formability of the glass can be further improved. Therefore, the molar ratio (Li 2 O+Na 2 O)/(Rn 2 O) preferably sets 0.75 as the lower limit, more preferably 0.88 as the lower limit, and further preferably 0.96 as the lower limit. Furthermore, the Moerby (Li 2 O+Na 2 O)/(Rn 2 The upper limit of O) is set to 1. <About the component which should not be contained> Next, the component which should not be contained in the optical glass of this invention, and the component which is not contained are demonstrated. Other components may be added as needed within the scope of the characteristics of the glass of the invention. However, each of the transition metal components such as V, Cr, Mn, Fe, Co, Ni, Cu, Ag, and Mo other than Ti, Zr, Nb, W, La, Gd, Y, Yb, and Lu is contained separately or in combination. In the case of a small amount, there is a property of coloring the glass to absorb a specific wavelength in the visible light range. Therefore, it is preferable that the optical glass having a wavelength in the visible light range is substantially not contained. Also, lead compounds such as PbO and As 2 O 3 Since the arsenic compound is a component having a high environmental load, it is preferably substantially not contained, that is, it is not contained at all except for inevitable mixing. Further, in recent years, various components of Th, Cd, Tl, Os, Be, and Se have been used as harmful chemical materials, and it is necessary to carry out environmental measures not only in the manufacturing steps of glass but also in processing steps and after product processing. Aspects of measures. Therefore, when it is important to pay attention to the influence of the environment, it is preferable that it does not substantially contain such. [Manufacturing Method] The optical glass of the present invention is produced, for example, in the following manner. In other words, the raw materials are uniformly mixed so that the respective components are within a specific content range, and the produced mixture is poured into platinum crucible, quartz crucible or alumina crucible, and coarsely melted, and then placed in a crucible or a platinum crucible. In a platinum alloy crucible or crucible, it is melted in a temperature range of 1100 to 1400 ° C for 3 to 5 hours, stirred to homogenize it, defoamed, etc., and then lowered to a temperature of 1000 to 1400 ° C, and then subjected to completion of stirring. It is produced by removing the veins, casting them into a mold, and slowly cooling them. In this case, as the glass raw material, it is preferred to use a higher meltability. Thereby, melting at a lower temperature or melting in a shorter time can be achieved, so that the productivity of the glass can be improved and the production cost can be reduced. Further, since the volatilization of the component or the reaction with hydrazine or the like is reduced, the glass having less coloration can be easily obtained. <Physical Properties> The optical glass of the present invention has a high refractive index and an Abbe number of a specific range. The refractive index of the optical glass of the present invention (n d Preferably, the lower limit is 1.62, more preferably 1.63, and further preferably 1.64. The upper limit of the refractive index is also preferably 1.75, more preferably 1.74, still more preferably 1.72, still more preferably 1.70, still more preferably 1.69. Abbe number of optical glass of the present invention (ν d It is preferably 42 or less, more preferably 40 or less, further preferably 39 or less, and further preferably 38 or less. On the other hand, the Abbe number of the optical glass of the present invention (v d It is preferable to use 30 as the lower limit, more preferably 32 as the lower limit, and still more preferably 34 as the lower limit. The optical glass of the present invention having such a refractive index and an Abbe number is useful for optical design, and in particular, it is possible to achieve high imaging characteristics and the like, and it is possible to reduce the size of the optical system, thereby increasing the degree of freedom in optical design. Here, the optical glass of the present invention preferably has a refractive index (n d And Abbe number (ν d ) satisfied (‐0.012ν d +2.04)≦n d ≦(-0.012ν d +2.14) relationship. The glass of the specific composition of the present invention has a refractive index (n d And Abbe number (ν d When the relationship is satisfied, a glass that is less prone to devitrification can be obtained. Therefore, the optical glass of the present invention preferably has a refractive index (n d And Abbe number (ν d ) meet nd≧(‐0.012ν) d +2.04) relationship, better to satisfy n d ≧(-0.012ν d +2.05) relationship, which is better to satisfy n d ≧(-0.012ν d +2.06) relationship. On the other hand, the optical glass of the present invention preferably has a refractive index (n d And Abbe number (ν d Satisfied n d ≦(-0.012ν d +2.14) relationship, better to satisfy n d ≦(-0.012ν d +2.13) relationship, which is better to satisfy n d ≦(-0.012ν d +2.12) relationship. The optical glass of the present invention has a lower partial dispersion ratio (θg, F). More specifically, the partial dispersion ratio (θg, F) of the optical glass of the present invention is preferably an upper limit of 0.594, more preferably an upper limit of 0.590, and still more preferably an upper limit of 0.586. The lower limit of the partial dispersion ratio (θg, F) may also preferably be 0.570, more preferably 0.573, still more preferably 0.575. Further, the partial dispersion ratio (θg, F) of the optical glass of the present invention is preferably an Abbe number (ν) d Between ) (-0.00162 × ν d +0.630)≦(θg,F)≦(-0.00162×ν d +0.652) relationship. Thereby, an optical glass having a lower partial dispersion ratio (θg, F) can be obtained, so that an optical element formed of the optical glass can be used to reduce chromatic aberration of the optical system. Therefore, the optical glass of the present invention preferably has a partial dispersion ratio (θg, F) and an Abbe number (ν). d ) satisfies θg, F≧(-0.00162×ν d +0.630), better to satisfy θg, F≧(‐0.00162×ν d +0.632), and it is better to satisfy θg, F≧(-0.00162×ν d +0.634) relationship. On the other hand, the optical glass of the present invention preferably has a partial dispersion ratio (θg, F) and an Abbe number (ν). d ) satisfies θg, F≦(-0.00162×ν d +0.652) The relationship is better to satisfy θg, F≦(‐0.00162×ν d +0.650), and it is better to satisfy θg, F≦(-0.00162×ν d +0.648), and it is better to satisfy θg, F≦(-0.00162×ν d +0.646), and it is better to satisfy θg, F≦(-0.00162×ν d +0.643) relationship. Furthermore, from the above partial dispersion ratio (θg, F) and Abbe number (ν d The relational expression indicates that by using the straight line having the same slope as the regular line to define the relationship, it is possible to obtain a glass having a partial dispersion ratio (θg, F) smaller than that of a general glass. The optical glass of the present invention preferably has a small specific gravity. More specifically, the specific gravity of the optical glass of the present invention is preferably 3.50 [g/cm 3 ]the following. Thereby, the quality of the optical device or the optical device using the same can be reduced, thereby contributing to weight reduction of the optical device. Therefore, the specific gravity of the optical glass of the present invention is preferably an upper limit of 3.50, more preferably an upper limit of 3.30, and still more preferably an upper limit of 3.10. Further, in the case of the optical glass of the present invention, the specific gravity is usually 2.50 or more, more specifically 2.70 or more, and more specifically 2.80 or more. The specific gravity of the optical glass of the present invention is measured based on the Japanese Optical Glass Industry Association Standard JOGIS05-1975 "Method for Measuring the Specific Gravity of Optical Glass". The optical glass of the present invention preferably has a glass transition point of 650 ° C or less. Thereby, since the glass softens at a lower temperature, the glass can be molded at a lower temperature. Moreover, the oxidation of the mold used for press molding can be reduced, and the life of the mold can be increased. Therefore, the glass transition point of the optical glass of the present invention is preferably 650 ° C as the upper limit, more preferably 620 ° C as the upper limit, and still more preferably 600 ° C as the upper limit. Furthermore, the lower limit of the glass transition point of the optical glass of the present invention is not particularly limited, and the glass transition point of the optical glass of the present invention may preferably be 460 ° C as the lower limit, more preferably 480 ° C as the lower limit, and thus Good is 500 ° C as the lower limit. The optical glass of the present invention preferably has a yield point (At) of 700 ° C or less. The yield point is one of the indexes indicating the softening property of the glass as in the case of the glass transition point, and is an index indicating the temperature close to the press molding temperature. Therefore, by using a glass having a yield point of 700 ° C or less, press forming at a lower temperature can be achieved, so that press forming can be performed more easily. Therefore, the yield point of the optical glass of the present invention is preferably an upper limit of 700 ° C, more preferably an upper limit of 680 ° C, and most preferably an upper limit of 660 ° C. Further, the yield point of the optical glass of the present invention is not particularly limited, but may preferably be 500 ° C as a lower limit, more preferably 530 ° C as a lower limit, and still more preferably 560 ° C as a lower limit. The optical glass of the present invention preferably has a small average coefficient of linear expansion (α). The average linear expansion coefficient of the optical glass of the present invention is particularly preferably 120 × 10 -7 K -1 For the upper limit, it is better to be 110×10 -7 K -1 The upper limit, and more preferably 100×10 -7 K -1 The upper limit. Thereby, when the optical glass is press-formed by a molding die, the total amount of expansion or contraction caused by the temperature change of the glass is reduced. Therefore, the optical glass can be prevented from being broken at the time of press molding, and the productivity of the optical element can be improved. The optical glass of the present invention preferably has good reheat and pressure formability. More specifically, the optical glass of the present invention preferably does not cause devitrification and opalescence even before the reheating test (the mold is immersed in the test). Therefore, even if the devitrification and coloring are not easily caused by the reheating test under the assumption of reheating and pressurization processing, the light transmittance of the glass is not easily lost, and the glass can be easily reheated by reheating and pressurizing processing. . That is, since an optical element having a complicated shape can be produced by press molding, it is possible to manufacture an optical element having a low manufacturing cost and high productivity. Here, the reheating test (mold immersion test) can be carried out by placing a 15 mm × 15 mm × 30 mm test piece on a concave refractory, placing it in an electric furnace for reheating, and heating from normal temperature for 150 minutes. It is higher than the yield point (At) of each sample by a temperature of 80 ° C to 150 ° C (falling into the temperature of the refractory), and after holding at this temperature for 30 minutes, it is cooled to normal temperature and taken out to the outside of the furnace to be In the internal observation method, the polished glass samples were visually observed after grinding the opposite surfaces to a thickness of 10 mm. In addition, the devitrification and the presence or absence of opacity before and after the reheating test (the mold is immersed in the test) can be visually confirmed, for example, "no devitrification and milky white" means a test piece such as a reheat test (mold immersion test). The transmittance of the light (d-ray) having a wavelength of 587.56 nm divided by the transmittance of the d-ray of the test piece before the reheating test is about 0.80 or more. The optical glass of the present invention preferably has a high chemical durability. More specifically, the optical glass of the present invention preferably has high water resistance or acid resistance. Thereby, when the optical glass is polished, the stain of the glass caused by the cleaning liquid or the polishing liquid is reduced, so that the polishing process can be performed more easily. In addition, the water resistance and acid resistance of the optical glass are preferably based on the chemical durability (water resistance and acid resistance) of JOGIS06-2008, which is a measurement method of the chemical durability of optical glass. It is 1 to 3, more preferably 1 to 2, and still more preferably 1. The optical glass of the present invention is preferably less susceptible to devitrification when the glass is produced. As a result, the decrease in the transmittance due to crystallization of the glass during the production of the glass is suppressed. Therefore, the optical glass can be preferably used for an optical element that transmits visible light such as a lens. Further, as a scale indicating that it is difficult to cause devitrification when the glass is produced, for example, the liquidus temperature is low. [Preformed material and optical element] A glass molded body can be produced from the produced optical glass by a method such as press molding such as reheat press molding or precision press molding. In other words, a preform for press molding can be produced from optical glass, and the preform can be subjected to reheating and press forming, followed by polishing to prepare a glass molded body; or, for example, polishing can be performed on the prepared preform. A glass molded body was produced by precision press molding. Furthermore, the method of producing a glass molded body is not limited to these methods. The glass molded body thus produced is useful for various optical elements, but among them, it is particularly preferably used for optical elements such as lenses or iridium. Thereby, the optical system provided with the optical element reduces the blur of the color caused by the chromatic aberration under the transmitted light. Therefore, when the optical element is used in a camera, the object to be imaged can be more accurately expressed, and when the optical element is used in a projector, the desired image can be projected in higher definition. [Examples] Compositions of the examples (No. 1 to No. 29) of the present invention, and refractive index (n) d ), Abbe number (ν d The results of partial dispersion ratio (θg, F), glass transition point (Tg), yield point (At), average linear expansion coefficient (α), specific gravity, and reheat test (mold trap test) are shown in Table 1 to In Table 5. Furthermore, the following examples are for illustrative purposes only and are not intended to be limited to the embodiments. As the raw materials of the respective components, the glass of the examples is selected from the respective oxides, hydroxides, carbonates, nitrates, fluorides, hydroxides, metaphosphoric compounds and the like which are generally used for high purity of optical glass. Weighed and uniformly mixed as a ratio of the composition of each of the examples and comparative examples shown in the table, and then charged into a platinum crucible, and used an electric furnace at a temperature of 1100 to 1400 ° C according to the ease of melting of the glass raw material. After melting for 3 to 5 hours in the range, the mixture is homogenized by stirring, and after defoaming or the like, the temperature is lowered to 1000 to 1400 ° C, stirred, homogenized, cast into a mold, and slowly cooled to prepare a glass. The refractive index of the glass of the example (n d ), Abbe number (ν d And the partial dispersion ratio (θg, F) is determined based on the Japan Optical Glass Industry Association standard JOGIS01-2003. Then, according to the obtained refractive index (n d And Abbe number (ν d Value, find the relation (n d =-a×ν d The slope a in +b) is the intercept b at 0.012. Also, based on the obtained Abbe number (ν d And the value of the partial dispersion ratio (θg, F), find the relation (θg, F = -a' × ν d The slope a' in +b') is the intercept b' at 0.00162. Further, the glass used in the measurement was subjected to treatment in a slow cooling furnace by setting the slow cooling rate to -25 ° C / hr. The glass transition point (Tg) and yield point (At) of the glass of the embodiment are in accordance with the Japanese Optical Glass Industry Association standard JOGIS08-2003 "Method for Measuring Thermal Expansion of Optical Glass" by Measuring the Relationship Between Temperature and Sample Elongation The obtained thermal expansion curve was obtained. The average linear expansion coefficient (α) of the glass of the example is obtained by the Japanese Optical Glass Industry Association standard JOGIS08-2003 "Method for Measuring Thermal Expansion of Optical Glass", and the average linear expansion coefficient of 100 to 300 ° C is obtained. The specific gravity of the glass of the examples was measured based on the Japanese Optical Glass Industry Association standard JOGIS05-1975 "Method for Measuring the Specific Gravity of Optical Glass". Further, regarding the glass of the example, the devitrification and the presence or absence of milkiness before and after the reheating test (molding test) were visually confirmed. Here, the devitrification and opacity confirmation before and after the reheating test is carried out by placing a 15 mm × 15 mm × 30 mm test piece on a concave refractory, placing it in an electric furnace and heating it to The temperature was reheated, and after holding at this temperature for 30 minutes, it was cooled to normal temperature, and taken out to the outside of the furnace, and the opposite sides were ground to a thickness of 10 mm so as to be observed inside, and the polished glass was visually observed. Devitrification of the sample and the presence or absence of milky white. At this time, the "mold into the test" of the following glass was designated as "○": when the reheating temperature of the test piece was set to (At + 80 ° C to 130 ° C), no devitrification and opalescence occurred, and another test piece was obtained. When the reheating temperature was set to (At+ exceeds 130 ° C to 150 ° C), no devitrification and whitening occurred. In addition, the "mold into the test" of the following glass is referred to as "△": when the reheating temperature of the test piece is set to (At + 80 ° C to 130 ° C), no devitrification and opalescence occur, but the other test piece will be re-applied. When the heating temperature is set to (At+ exceeds 130 ° C to 150 ° C), devitrification or opalescence occurs. In addition, the "mold test in the glass" of the following glass is referred to as "x": even when the reheating temperature of the test piece is set to (At + 80 ° C to 90 ° C), devitrification or opalescence occurs. [Table 1] [Table 2] [table 3] [Table 4] [table 5] As shown in the above tables, the partial dispersion ratio (θg, F) of the optical glass of the examples (No. 1 to No. 29) was 0.594 or less, which was within the desired range. Here, the partial dispersion ratio (θg, F) and the Abbe number of the optical glass of the embodiment of the present invention (ν) d ) satisfied (-0.00162 × ν d +0.630)≦(θg,F)≦(-0.00162×ν d +0.652) relationship, in more detail, satisfies (θg, F) ≦ (-0.00162 × ν d +0.651) relationship. Moreover, the partial dispersion ratio (θg, F) and the Abbe number of the glass of the embodiment of the present invention (v d The relationship becomes as shown in Figure 2. Therefore, it is apparent that the optical glass of the embodiment of the present invention has a small partial dispersion ratio (θg, F). Refractive index of optical glass according to an embodiment of the present invention (n d ) are both above 1.62, more specifically 1.64 or more, and the refractive index (n) d ) is 1.75 or less, which is within the required range. Further, the Abbe number of the optical glass of the embodiment of the present invention (v d ) are all 30 or more, more specifically 34 or more, and the Abbe number (ν) d ) is 42 or less, and more specifically 41 or less, which is within the required range. Here, the refractive index of the optical glass of the embodiment of the present invention (n d And Abbe number (ν d ) satisfied (‐0.012ν d +2.04)≦n d ≦(-0.012ν d +2.14) relationship, more detailed (‐0.012ν d +2.08)≦n d ≦(-0.012ν d +2.13) relationship. Moreover, the refractive index of the glass of the embodiment of the present invention (n d And Abbe number (ν d The relationship becomes as shown in Figure 3. Therefore, it is clear that the refractive index of the optical glass system of the embodiment (n d And Abbe number (ν d An optical glass having a small partial dispersion ratio (θg, F) within a desired range. Among them, in particular, the optical glass of the examples (No. 1 to No. 8) was less likely to cause devitrification and milkiness after the reheating test (mold immersion test). On the other hand, the optical glass of the examples (No. 9 to No. 10) is devitrified or opaque in at least a part of the temperature range higher than the yield point (At) of the sample by 80 ° C to 150 ° C. . Therefore, the optical glass of the examples (No. 1 to No. 8) is less likely to cause devitrification or opalescence due to reheating than the examples (No. 9 to No. 10), and thus it is presumed that it is high. Reheating and press formability. Further, the specific gravity of the optical glass of the examples was 3.50 or less, and more specifically 3.30 or less, which was within the required range. Further, the glass transition point of the optical glass of the example is 650 ° C or lower, and more specifically 630 ° C or lower. Further, the yield point of the optical glass of the examples was 700 ° C or less, which was within the required range. From these, it can be inferred that the glass can be molded at a lower temperature. Further, the average linear expansion coefficient (α) of the optical glass of the example is 120 × 10 -7 K -1 Hereinafter, in more detail, 110×10 -7 K -1 Below, within the required range. Further, when the lens preform is formed using the optical glass of the embodiment and the lens preform is subjected to press molding, it can be processed into various lens shapes without devitrification or opalescence. The present invention has been described in detail above with reference to the embodiments of the present invention.